//
// "$Id: filename_expand.cxx 9325 2012-04-05 05:12:30Z fabien $"
//
// Filename expansion routines for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2010 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     http://www.fltk.org/COPYING.php
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//

/* expand a file name by substuting environment variables and
   home directories.  Returns true if any changes were made.
   to & from may be the same buffer.
*/
#include "Fl_Platform.h"

#include "filename.H"
#include "fl_utf8.h"
#include <stdlib.h>
#include "flstring.h"

#if __FLTK_WIN32__
#include <windows.h>
#elif __FLTK_WINCE__
#include <windows.h>
#else
# include <unistd.h>
# include <pwd.h>
#endif

#if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
static inline int isdirsep(char c)
{
	return c=='/' || c=='\\';
}
#else
#define isdirsep(c) ((c)=='/')
#endif

/** Expands a filename containing shell variables and tilde (~).
    Currently handles these variants:
    \code
    "~username"               // if 'username' does not exist, result will be unchanged
    "~/file"
    "$VARNAME"                // does NOT handle ${VARNAME}
    \endcode

    \b Examples:
    \code
    #include <filename.H>
    [..]
    putenv("TMPDIR=/var/tmp");
    fl_filename_expand(out, sizeof(out), "~fred/.cshrc");     // out="/usr/fred/.cshrc"
    fl_filename_expand(out, sizeof(out), "~/.cshrc");         // out="/usr/<yourname>/.cshrc"
    fl_filename_expand(out, sizeof(out), "$TMPDIR/foo.txt");  // out="/var/tmp/foo.txt"
    \endcode
    \param[out] to resulting expanded filename
    \param[in]  tolen size of the expanded filename buffer
    \param[in]  from filename containing shell variables
    \return 0 if no change, non zero otherwise
 */
int fl_filename_expand(char *to,int tolen, const char *from)
{

	char *temp = new char[tolen];
	strlcpy(temp,from, tolen);
	char *start = temp;
	char *end = temp+strlen(temp);

	int ret = 0;

	for (char *a=temp; a<end; ) {	// for each slash component
		char *e;
		for (e=a; e<end && !isdirsep(*e); e++); // find next slash
		const char *value = 0; // this will point at substitute value
		switch (*a) {
		case '~':	// a home directory name
			if (e <= a+1) {	// current user's directory
				value = fl_getenv("HOME");
#ifndef WIN32
			} else {	// another user's directory
				struct passwd *pwd;
				char t = *e;
				*(char *)e = 0;
				pwd = getpwnam(a+1);
				*(char *)e = t;
				if (pwd) value = pwd->pw_dir;
#endif
			}
			break;
		case '$': {	/* an environment variable */
			char t = *e;
			*(char *)e = 0;
			value = fl_getenv(a+1);
			*(char *)e = t;
		}
		break;
		}
		if (value) {
			// substitutions that start with slash delete everything before them:
			if (isdirsep(value[0])) start = a;
#if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
			// also if it starts with "A:"
			if (value[0] && value[1]==':') start = a;
#endif
			int t = (int) strlen(value);
			if (isdirsep(value[t-1])) t--;
			if ((end+1-e+t) >= tolen) end += tolen - (end+1-e+t);
			memmove(a+t, e, end+1-e);
			end = a+t+(end-e);
			*end = '\0';
			memcpy(a, value, t);
			ret++;
		} else {
			a = e+1;
#if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
			if (*e == '\\') {
				*e = '/';        // ha ha!
				ret++;
			}
#endif
		}
	}

	strlcpy(to, start, tolen);

	delete[] temp;

	return ret;
}


//
// End of "$Id: filename_expand.cxx 9325 2012-04-05 05:12:30Z fabien $".
//
